1. Field of the Invention
The present invention broadly relates to the mounting, and adjustment of the position, of an optical element, such as a prism, and, more particularly, is concerned with an adjustable holder for allowing universal adjustment of the angular position of the prism, that is, in roll, pitch and yaw, simultaneously.
2. Description of the Prior Art
The patent to von Hofe et al, U.S. Pat. No. 1,744,994; Mikic, U.S. Pat. No. 2,997,912; Gunther, U.S. Pat. No. 3,194,108; Crosswhite, U.S. Pat. No. 3,473,865; and Peifer et al, U.S. Pat. No. 3,515,464, relate to various instruments and devices which utilize one or more optical elements, such as prisms. Most of the prisms are adjustable only about one rotational axis. None of the instruments have a prism mounting arrangement which allows adjustment of the prism about three mutually perpendicular axes.
Arrangements which accommodate adjustment of the optical element about more than one axis commonly utilize a number of adjustable screws which together hold the element in the desired angular position. However, to readjust or correct the position of the optical element for whatever reason, a tedious, time-consuming procedure of individually and repetitively adjusting each screw must be undertaken. Unfortunately each time an angular correction is made in one direction, the alignment in another direction is adversely affected. As a result, each screw has to be adjusted and readjusted an unpredictable number of times. The inordinate length of time that ordinarily has to be spent in adjusting the position of the element wears on the operator's patience and sometimes contributes to the adjustments being made with less than the required precision. Therefore, a need exists for an adjustable mechanism or device which would facilitate accurate readjustment or correction of the position of the optical element in a reasonably short and predictable length of time.